Thai authorities expressed relief Monday as floodwaters in the Chao Phraya River passed their crest stage and began receding without breaching the barriers protecting Bangkok.

However, some wary residents are continuing to fortify the capital's flood walls with sandbags, despite assurances from officials that the city will not be inundated.

One resident said he will keep working until he is sure his neighborhood is safe.

Officials say more than 300 people have died in the country's worst flooding in half a century. In provinces north of the capital, thousands of people remain hungry and homeless in half-submerged towns.

Valerie Amos, the U.N. under-secretary-general for humanitarian affairs, said late Saturday that more than 700 people have died in flooding in Cambodia and Thailand.

The statement said that in Laos, the Philippines and Vietnam, homes, crops and vital infrastructure have been destroyed. Millions of people living in low-lying areas remain vulnerable to further destruction.

Amos said the U.N. stands ready to support national-led responses.